# Siunitx's \micro symbol has serif

I am trying to reproduce the look of the micro symbol in the siunitx documentation; see for instance the following picture:

However, when compiling the following code:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}

\usepackage{textcomp}
\usepackage{siunitx}

\begin{document}

\SI{15}{\micro\metre}

\end{document}


the mu comes out with serif as in the following picture:

I suppose there is a font issue here but I could find how to solve it by reading the siunitx documentation.

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You can adjust the definition, but why do you expect there to be no serif here? – Joseph Wright Feb 28 '13 at 18:46
Different font, try replacing lmodern with mathpazo. – Torbjørn T. Feb 28 '13 at 18:50
Admitedly serif in a serif text is rather normal. However some people find that the serif on the mu look odd and also (mainly) the mu in the documentation are sans-serif even in serif text. I was wondering how you achieved that. – Alfred M. Feb 28 '13 at 18:50

In this particular case, you're using a font different to that of the manual. Replace lmodern with mathpazo to get the same font. (This will of course influence the entire document.)
Finding the 'correct' micro symbol is tricky as a lot of fonts do not include the appropriate (upright, roman font, 'matching') micro or mu. The siunitx package therefore provides two options which control the symbol used here: math-micro and text-micro. These are used to set the symbol in math and text mode, respectively. Simply pick a formulation you like and use \sisetup to activate it
\sisetup{math-micro = <your-choice-here>, text-micro = <your-choice-here>}